1. Field of the Invention
The present invention relates to a thin-film transistor (TFT) substrate including pixel electrodes which are made of carbon nanotubes or graphene, and a method of manufacturing the TFT substrate.
2. Description of the Related Art
Liquid crystal displays (LCDs) are one of the most widely used types of flat panel displays (FPDs). Generally, an LCD includes two substrates, which each have electrodes, and a liquid crystal layer interposed between the substrates. Voltages are applied to the electrodes to rearrange liquid crystal molecules in the liquid crystal layer, thereby controlling the amount of light that passes through the liquid crystal layer.
The most commonly used type of LCDs at present include two substrates, each having electric field generating electrodes. On one of the two substrates, a plurality of pixel electrodes are arranged in a matrix pattern. On the other substrate, one common electrode covers the entire surface of the substrate. These electric field generating electrodes are usually formed of indium tin oxide (ITO) or indium zinc oxide (IZO) by a sputtering method. However, ITO and IZO are increasingly becoming more expensive due to an increase in the consumption of indium. In addition, forming an electrode using ITO or IZO involves high-priced equipment, a complicated process, and a long process time.
In this regard, attempts have been made to replace ITO or IZO as the material used to form electric field generating electrodes with carbon nanotubes or graphene. However, despite their low cost, stable conductivity, and high transmittance, film uniformity is difficult to ensure when using carbon nanotubes or graphene on a thin-film transistor (TFT) substrate, and thus contact resistance is increased.